The influence of whispering gallery modes on the far field of ring lasers

Abstract

We introduce ring lasers with continuous π-phase shifts in the second order distributed feedback grating. This configuration facilitates insights into the nature of the modal outcoupling in an optical cavity. The grating exploits the asymmetry of whispering gallery modes and induces a rotation of the far field pattern. We find that this rotation can be connected to the location of the mode relative to the grating. Furthermore, the direction of rotation depends on the radial order of the whispering gallery mode. This enables a distinct identification and characterization of the mode by simple analysis of the emission beam.

Advanced gas sensors based on substrate-integrated hollow waveguides and dual-color ring quantum cascade lasers

“…The latter voltage measurements were performed using a digital oscilloscope (PicoScope 5444B, Picotech, Cambridgeshire, UK). The riQCL features a dual DFB grating 16 promoting/facilitating dual-color vertical emission of MIR radiation. The two distinct emission wavelengths at 1144 cm −1 (5.5 kA cm −2 ), and at 1170 cm −1 (10 kA cm −2 ) are attributed to the 1 st and 2 nd order whispering gallery modes, respectively.…”

“…1) utilizing a second order distributed feedback (DFB) grating fabricated into the ring waveguide for efficient vertical light outcoupling. [9][10][11] Besides facilitating pronounced optical power 12 and excellent a beam collimation, [13][14][15][16][17][18] the integration of vertically emitting laser diodes facilitates their application within ultra-compact sensing concepts using a minimum of beam-guiding optical elements. From the perspective of optical efficiency, in addition a rotationally symmetric far field is achieved via dielectric meta-materials, thereby minimizing scattering losses.…”

Поверхностно-Излучающий Квантово-Каскадный Лазер С Кольцевым Резонатором

“…К настоящему моменту успешно реализованы поверхностно-излучающие ККЛ среднего инфракрасного диапазона [5,6], в том числе, в конструкции с кольцевым резонатором [7][8][9][10][11][12][13]. Интерес к исследованиям ККЛ с кольцевым резонатором обусловлен в первую очередь возможностью их применения при детектировании и анализе химических газов [14].…”

Remote Sensing with Commutable Monolithic Laser and Detector

“…The sensor geometry is designed to enable efficient mutual commutation between laser and detector. Two concentric ring waveguides 20 are used for both vertical emission and detection; that is, both monolithic rings can be operated as laser and detector. Overcoming the distinction between emitter and detector, this concept facilitates a crucial miniaturization and simplification of sensing devices.…”